Patients in hospitals are often provided with medical fluids that are administered through an IV infusion. The medical fluids may include a saline solution to hydrate the patient or a more complex mixture, such as Ringer's Lactate, that may include electrolytes or nutritional supplements. It is sometimes desirable to intravenously administer a small amount of a second medical fluid to a patient already receiving a relatively large amount of a first medical fluid via IV infusion. Rather than administer the second medical fluid through a separate direct injection, the second medical fluid can be injected into the flow of the first medical fluid. A syringe, or other fluid container having an IV line and a luer connector, can be used to actuate a needleless access port in an IV set that connects the container of the first medical fluid to the patient and inject the second medical fluid through the access port. IV sets are commonly provided with one or more needleless access ports for this and other uses.
Needleless access ports typically have internal spaces surrounding the self-sealing elements of the access port. These internal spaces are typically connected through a single opening to the primary line of the IV set such that the flow through the internal space is to or from the needleless connector that is actuating the access port. When the IV set is initially set up, this space may not be flushed with fluid introduced into the primary line, leaving this space filled with air. This requires manual flushing of the access port, either by introduction of fluid into the access port to force this air into the primary line where it is carried away and expelled during the set-up or connection of an empty syringe and extraction of the air through the access port.
When a second medical fluid is injected through the needleless access port, a certain amount of the injected second medical fluid remains in the interior space and does not reach the patient. To administer the entire prescribed dose of the second medical fluid to the patient, the caregiver must connect a second syringe, or other fluid container having a Luer fitting, containing a flushing fluid, for example saline, and inject a sufficient quantity of this flushing fluid to flush the interior space and carry the second medical fluid into the main line of the IV set. This creates an additional work step for the caregiver and adds a risk to the patient of infection due to the additional manipulation of the device.
Alternately, a caregiver may administer an extra amount of the second medical fluid such that the prescribed dose reaches the main line of the IV set. This creates a risk that a second caregiver, not realizing that there is residual second medical fluid in the access port, may also administer an extra amount of the second medical fluid and thereby administer more than the intended amount.